1. Field of Invention
The present invention relates to a charger, and more particularly to a multi-battery charger which is capable of charging battery of different sizes, and irrespective of polarity of the battery terminals.
2. Description of Related Arts
A conventional charger, such as a conventional battery charger for a cellular phone battery, usually comprises a charger case having a battery slot formed thereon, a positive charging pin and a negative charging pin spacedly provided within the battery slot for aligning with a battery terminal and a negative battery terminal of the battery respectively, and a charging circuitry provided within the charger case to electrically connect with the positive charging pin and the negative charging pin. When the battery is is placed properly within the battery slot, the charging circuitry can be activated to start charging of the battery through the positive charging pin and the negative charging pin.
There exist several disadvantages for this type of conventional charger. First, in order to properly charge the a conventional rechargeable battery, a user must insert the battery into the battery slot and ensure that the positive charging pin and the negative charging pin of the conventional charger align with the positive battery terminal and the negative battery terminal of the rechargeable battery respectively. This presents an inconvenience charging practice to users of cellular phones and creates a potentially dangerous scenario when the users accidentally or carelessly put the rechargeable battery into the charging slot in reverse polarity. In such a case, the rechargeable battery may not be properly recharged, and in the worst scenario, the rechargeable battery may even have the possibility of having explosion.
Second, almost all conventional chargers have been specifically designed to recharge only one particular type or model of rechargeable batteries. For example, a charger of a particular rechargeable battery designed for use in a particular model or particular brand of cellular phones may only be utilized for charging that particular type of rechargeable battery. This may be accomplished in a number of ways. Mechanically, the battery slot of the charger may be specifically crafted and designed to fit only one type of batteries. Rechargeable batteries of other types simply cannot be inserted into the battery slot for electrically connecting the battery terminals with the charging pins. Electronically, the charging circuitry of the conventional charger may be specifically designed and engineered to charge rechargeable batteries which only possess certain charging parameters. Thus, when a user possesses several cellular phones, he or she may need to get the corresponding number of battery chargers in order to recharge all of their batteries. This presents an undue inconvenience to cellular phone users.
As a matter of fact, there exists an improved charger which has a plurality of battery slots formed on the charger case for charging batteries of different sizes and capacities. The charging circuitry is also electronically designed to charge more than one battery simultaneously. However, the main problem of this type of battery charger is that each particular battery slot is usually designed for charging a particular type of battery having a particular capacity. Thus although this type of battery charger mitigates some of the disadvantages mentioned above, it does not resolve the relevant problems acceptably because it does not address the core nature of the problem, i.e. the inherent inflexible nature of conventional chargers. Thus, when a battery of unmatched capacity is put into one particular battery slot, either the rechargeable battery or the charging circuitry may be severely damaged.